This invention relates to a cleaning shoe for a combine harvester and more particularly to an improved cleaning shoe having an upper sieve element providing for positive conveying of crop material as well as oscillation and a blower system providing longitudinally spaced air blasts over the length of the underside of a lower sieve element.
It is known to oscillate at least the upper run of a sieve belt normal to the plane of the belt to further assist in the separation. For example, German Pat. No. 2,015,584 discloses an oscillating pronged belt shaker for separating grain from stalk and leaf material in a combine harvester, with prongs which are arranged on prong carriers and which are oscillated for shaking out the grain and straw by self-excitation or by means of positive excitation. For this purpose, rollers are disposed above the upper run, which rollers may also be of elliptical configuration. This causes the upper run which is driven by conveyor rollers also to be displaced in a vertical direction.